Known in the art is a device for removing external circular fins from the joints of the pipes being welded together, comprising a base, a hollow rotor with a faceplate running in the base bearings, carriages mounted on the rotor faceplate, a mechanism for effecting a radial traverse of the carriages, having a holder fitted on the rotor so as to rotate with respect thereto, and a drive for the rotor and for the carriage radial traversing mechanism.
A main disadvantage inherent in such devices for removing external circular fins resides in the incomplete removal of the fins whenever the pipe joints are found to have an oval shape, inasmuch as the cutting tools (cutters) are held in the carriages which describe strictly predetermined orbital paths around the pipes being welded and therefore are incapable of tracing the pipe surface, which in fact departs from a true circumference.
In the known device, the cutter is fed at a constant rate, therefore when removing an external circular fin having a cross-sectional shape approximating a triangular one, the cutting force applied and the power consumed are essentially variable values.
This results in overloading the drive when the tool is fed at high rates and, accordingly, in underloading the drive at lower feed rates of the cutter. To obviate said disadvantage said known devices provide for manual cutter feed control in the course of operation, which badly affects the productive efficiency of the device and deteriorates the quality of machining.
Moreover, the device incorporates two self-contained drives, viz., the rotor drive and the carriage radial traverse drive. Therefore, special mechanisms must be provided to bring the rotational speeds of both drives in synchronism. This adds to the bulkiness of the device and makes its construction and service costs still higher.
In addition, said mechanisms fail to provide aa programmed misalignment of the rotor and holder rotational speed to suit particular operating conditions. At best, they would be able to perform a preset program under given operating conditions; whenever the latter vary, the entire feed drive needs resetting.